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Optical and Electrical Characterization of Transition Metal and Rare-Earth Metal Doped II-VI Semiconductors for Mid-IR Laser Applications.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Optical and Electrical Characterization of Transition Metal and Rare-Earth Metal Doped II-VI Semiconductors for Mid-IR Laser Applications./
作者:	Gafarov, Ozarfar.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2020,
面頁冊數:	126 p.
附註:	Source: Dissertations Abstracts International, Volume: 81-12, Section: B.
Contained By:	Dissertations Abstracts International81-12B.
標題:	Optics. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27834575
ISBN:	9798645472344

Optical and Electrical Characterization of Transition Metal and Rare-Earth Metal Doped II-VI Semiconductors for Mid-IR Laser Applications.
Gafarov, Ozarfar.

Optical and Electrical Characterization of Transition Metal and Rare-Earth Metal Doped II-VI Semiconductors for Mid-IR Laser Applications. - Ann Arbor : ProQuest Dissertations & Theses, 2020 - 126 p.

Source: Dissertations Abstracts International, Volume: 81-12, Section: B.

Thesis (Ph.D.)--The University of Alabama at Birmingham, 2020.

This item must not be sold to any third party vendors.

The middle-infrared (mid-IR) 2-8 μm and long-wavelength-infrared (LWIR) 8-20 μm spectral range enjoys a lot of attention from the scientific, medical, and industrial communities. A number of applications such as spectroscopy, medical diagnosis, surgical procedures, materials processing, remote detection of organic compounds, free-space-communication, and many others are possible. Transition metal (TM) doped II-VI semiconductors are the materials of choice for accessing the mid-IR. The II-VI host materials feature broad infrared transparency, low phonon frequency, and low optical losses. When doped with TM ions, these media exhibit a four-level energy structure, the absence of excited state absorption, and broad absorption and emission bands. Fabrication technology of the host materials is well-established, and they are commercially available. Doping with TM ions can be done during crystal growth, however, growth of large crystals with good optical quality is hard. An alternative method for fabrication is based on post-growth thermal-diffusion-doping (TDD) of II-VI materials with TM ions. This method yields uniformly doped crystals with preassigned dopant concentration while preserving the good optical quality of the host. However, not all combinations of TM and II-VI hosts can be easily doped via TDD. For example, Fe diffusion in ZnSe takes ~30 days yielding uniform doping through 2 mm, in ZnS during the same time only ~100 μm of diffusion is possible. This hinders the fabrication of sufficiently large crystals with uniform doping, and desired concentrations. Rare earth ions (RE) constitute another family of dopants for mid-IR lasing. However, due to their large ionic radii, it is hard to dope RE ions via thermal diffusion. No reports on significant TDD of RE ions in II-VI materials apppear in the literature.The ability to use TDD for a wider range of dopant ions could greatly benefit mid-IR lasers based on II-VI host materials, potentially adding to the impressive list of output characteristics as well as allowing the use of a wider range of optical pump sources. The first major objective of this work is achieving enhancements diffusion of TM and RE ions in II-VI materials through enhancing conditions such as subjecting the host material to gamma radiation, high energy electron beam, high electric field, overpressure of fast diffusing elements, and elevation of temperature and pressure, during the thermal diffusion process.Despite the slow rate of diffusion of many TM and RE ions in II-VI, significant results have been achieved based on the development of fabrication methods of Cr:ZnSe, Cr:ZnS, and Fe:ZnSe. These results include access to a broad spectral range of 1.8-6 μm with more than 60 % efficiency, tunability exceeding 1000 nm, output powers exceeding 140 W in continuous-wave operation, multi-Joule output energies in free-running and gain-switched regimes, short-pulses of < 16 fs in multi-Watt oscillation. All of these results are achieved under optical pumping. Due to the wide band-gap and low phonon frequencies, these materials have the potential for electrical excitation. Achievement of electrical pumping eliminates the need for external pump lasers, potentially reducing the fabrication cost. Electrical excitation can be carried out through recombination of the charge carrier in p-n junction or by impact excitation of hot carriers. The impact excitation mechanism in these materials requires monocrystalline bulk crystals with appropriate conductivity, high enough optically active dopant concentration, low optical losses, and formation of Ohmic contacts. The second major objective of this work is devoted to understanding the physical processes and conditions necessary for the realization of lasing under direct electrical excitation.

ISBN: 9798645472344Subjects--Topical Terms:

517925
Optics.
Subjects--Index Terms:

Electroluminescence

Optical and Electrical Characterization of Transition Metal and Rare-Earth Metal Doped II-VI Semiconductors for Mid-IR Laser Applications.
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245 1 0 $a Optical and Electrical Characterization of Transition Metal and Rare-Earth Metal Doped II-VI Semiconductors for Mid-IR Laser Applications.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2020
300 $a 126 p.
500 $a Source: Dissertations Abstracts International, Volume: 81-12, Section: B.
500 $a Advisor: Mirov, Sergey B.
502 $a Thesis (Ph.D.)--The University of Alabama at Birmingham, 2020.
506 $a This item must not be sold to any third party vendors.
520 $a The middle-infrared (mid-IR) 2-8 μm and long-wavelength-infrared (LWIR) 8-20 μm spectral range enjoys a lot of attention from the scientific, medical, and industrial communities. A number of applications such as spectroscopy, medical diagnosis, surgical procedures, materials processing, remote detection of organic compounds, free-space-communication, and many others are possible. Transition metal (TM) doped II-VI semiconductors are the materials of choice for accessing the mid-IR. The II-VI host materials feature broad infrared transparency, low phonon frequency, and low optical losses. When doped with TM ions, these media exhibit a four-level energy structure, the absence of excited state absorption, and broad absorption and emission bands. Fabrication technology of the host materials is well-established, and they are commercially available. Doping with TM ions can be done during crystal growth, however, growth of large crystals with good optical quality is hard. An alternative method for fabrication is based on post-growth thermal-diffusion-doping (TDD) of II-VI materials with TM ions. This method yields uniformly doped crystals with preassigned dopant concentration while preserving the good optical quality of the host. However, not all combinations of TM and II-VI hosts can be easily doped via TDD. For example, Fe diffusion in ZnSe takes ~30 days yielding uniform doping through 2 mm, in ZnS during the same time only ~100 μm of diffusion is possible. This hinders the fabrication of sufficiently large crystals with uniform doping, and desired concentrations. Rare earth ions (RE) constitute another family of dopants for mid-IR lasing. However, due to their large ionic radii, it is hard to dope RE ions via thermal diffusion. No reports on significant TDD of RE ions in II-VI materials apppear in the literature.The ability to use TDD for a wider range of dopant ions could greatly benefit mid-IR lasers based on II-VI host materials, potentially adding to the impressive list of output characteristics as well as allowing the use of a wider range of optical pump sources. The first major objective of this work is achieving enhancements diffusion of TM and RE ions in II-VI materials through enhancing conditions such as subjecting the host material to gamma radiation, high energy electron beam, high electric field, overpressure of fast diffusing elements, and elevation of temperature and pressure, during the thermal diffusion process.Despite the slow rate of diffusion of many TM and RE ions in II-VI, significant results have been achieved based on the development of fabrication methods of Cr:ZnSe, Cr:ZnS, and Fe:ZnSe. These results include access to a broad spectral range of 1.8-6 μm with more than 60 % efficiency, tunability exceeding 1000 nm, output powers exceeding 140 W in continuous-wave operation, multi-Joule output energies in free-running and gain-switched regimes, short-pulses of < 16 fs in multi-Watt oscillation. All of these results are achieved under optical pumping. Due to the wide band-gap and low phonon frequencies, these materials have the potential for electrical excitation. Achievement of electrical pumping eliminates the need for external pump lasers, potentially reducing the fabrication cost. Electrical excitation can be carried out through recombination of the charge carrier in p-n junction or by impact excitation of hot carriers. The impact excitation mechanism in these materials requires monocrystalline bulk crystals with appropriate conductivity, high enough optically active dopant concentration, low optical losses, and formation of Ohmic contacts. The second major objective of this work is devoted to understanding the physical processes and conditions necessary for the realization of lasing under direct electrical excitation.
590 $a School code: 0005.
650 4 $a Optics. $3 517925
650 4 $a Materials science. $3 543314
653 $a Electroluminescence
653 $a Middle-Infrared Lasers
653 $a Rare Earth Doping
653 $a Spatial Hole Burning
653 $a Thermal Diffusion
653 $a Transition Metal Doping
690 $a 0752
690 $a 0794
710 2 $a The University of Alabama at Birmingham. $b Physics. $3 1674816
773 0 $t Dissertations Abstracts International $g 81-12B.
790 $a 0005
791 $a Ph.D.
792 $a 2020
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27834575